The Basics of Chronic Fatigue Syndrome

Chronic fatigue is an illness characterized by prolonged, debilitating fatigue and multiple nonspecific symptoms.
Chronic fatigue is an illness characterized by prolonged, debilitating fatigue and multiple nonspecific symptoms.

Chronic fatigue syndrome (CFS) is an illness characterized by prolonged, debilitating fatigue and multiple nonspecific symptoms such as headaches, recurrent sore throats, muscle and joint pains, memory and concentration difficulties. Profound fatigue, the hallmark of the disorder, can come on suddenly or gradually and persists or recurs throughout the period of illness. Unlike the short-term disability of say, the flu, CFS symptoms linger for at least six months and often for years. The cause of CFS remains unknown.

The typical patient seeking medical care for CFS is a Caucasian woman in her mid-20s to late 40s. However, anyone at any age — male or female — can develop chronic fatigue syndrome, though cases reported in children under 12 are rare.


The illness was named chronic fatigue syndrome because it reflects the most common symptom — long-term, persistent fatigue. When the International CFS Study Group updated the definition of chronic fatigue syndrome in 1994, it decided to keep this name until a specific cause for the illness is discovered. (Today, chronic fatigue syndrome also is known as myalgic encephalomyelitis, postviral fatigue syndrome, and chronic fatigue and immune dysfunction syndrome.)

There are no published data to indicate that CFS is contagious, that it can be transmitted through intimate or casual contact or by blood transfusion, or that people with chronic fatigue syndrome need to be isolated in any way.

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Prevalence of Chronic Fatigue Syndrome

The U.S. Centers for Disease Control and Prevention (CDC) conducted a study from 1989 to 1993 to estimate the prevalence of chronic fatigue syndrome; they estimated that four to 8.7 of every 100,000 adults living in the U.S. suffered from chronic fatigue syndrome. However, more recent studies indicate that these projections are underestimated. The prevalence of chronic fatigue syndrome is difficult to measure because the illness can be difficult to diagnose, but in general, it is estimated that perhaps as many as half a million persons in the U.S. have a CFS-like condition, according to the CDC.

Chronic fatigue syndrome does not appear to be a new illness, although it has only recently been assigned the name CFS. Relatively small outbreaks of similar disorders have been described in medical literature since the 1930s. Furthermore, case reports of comparable illnesses date back several centuries.


Interest in what now is called CFS was renewed in the mid-1980s after several studies found slightly higher levels of antibody to Epstein-Barr virus (EBV) in patients with CFS-like symptoms than in healthy individuals. Most of these patients had experienced an episode of infectious mononucleosis (sometimes called mono or the "kissing disease") a few years before they began to experience the chronic, debilitating symptoms of chronic fatigue syndrome. As a result, for a time the CFS-like illness became popularly termed "chronic EBV".

Further investigation revealed that elevated EBV antibodies were not indicators of chronic fatigue syndrome. Some healthy people have high EBV antibodies and some people with CFS do not. Currently, it is not considered useful to test for antibodies to EBV in a patient with symptoms suggestive of chronic fatigue syndrome.

Copyright 2003 National Women's Health Resource Center Inc. (NWHRC)


Chronic Fatigue Syndrome Symptoms

Chronic fatigue syndrome often begins abruptly, but sometimes the onset is gradual. In about one-third of cases, the sudden onset follows a respiratory, gastrointestinal or other acute infection with flu-like symptoms, including mononucleosis. Other cases develop after emotional or physical traumas such as bereavement or surgery.

Besides a debilitating fatigue, which is unalleviated by rest, common symptoms of chronic fatigue syndrome include:


  • more intense or changed patterns of headaches
  • reduced short-term memory or concentration
  • recurrent sore throats
  • tender lymph nodes
  • muscle discomfort or pain
  • joint pain without joint swelling or redness
  • unrefreshing sleep

The severity of chronic fatigue syndrome symptoms varies broadly among individuals.

Some chronic fatigue syndrome patients also report mild to moderate symptoms of anxiety or depression. However, it is important to note that 60 percent of carefully evaluated chronic fatigue syndrome patients do not have depression or another psychiatric illness.

Some studies have found that allergies are significantly more common in CFS patients than in the general population. Many CFS patients have a history of allergies years before the onset of the syndrome. Sometimes patients report a worsening of allergic symptoms or the onset of new allergies after becoming ill with chronic fatigue syndrome. Because allergies are so common in people with chronic fatigue syndrome, it is important to identify symptoms caused by allergies so they can be treated independently.

Although CFS can persist for many years, long-term studies indicate that chronic fatigue syndrome generally is not a progressive illness. The symptoms usually are most severe in the first year or two. Thereafter, the symptoms typically stabilize and then persist chronically, wax and wane, or improve. Most patients partially recover, only a few fully recover and others recover and relapse. Currently, an individual's course of illness cannot be predicted. No long-term health risks have been associated with having chronic fatigue syndrome.

Copyright 2003 National Women's Health Resource Center Inc. (NWHRC)


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